相关实验视频
Updated: May 15, 2025

10:42
Preparing an Isotopically Pure 229Th Ion Beam for Studies of 229mTh
Published on: May 3, 2019
6.6K
实时核电子轨道中的节能 Ehrenfest 动态
Tao E Li1, Xiaosong Li2, Sharon Hammes-Schiffer3
1Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA.
The Journal of chemical physics
|April 8, 2025
概括
一种新的恒温旅行质子基础 (TPB) 方法改善了量子质子转移模拟的实时核电子轨道Ehrenfest (RT-NEO-Ehrenfest) 动态中的能量节约.
科学领域:
- 量子化学是一种量子化学.
- 理论化学是一种理论化学.
- 计算化学是一种计算化学.
背景情况:
- 实时核电子轨道埃伦费斯特 (RT-NEO-Ehrenfest) 动力学方法使非核电动分子过程的第一原则模拟成为可能.
- 移动质子基础 (TPB) 方法通过允许量子质子基础函数以经典的方式移动来增强质子转移的RT-NEO-Ehrenfest动态.
- 现有的 TPB 方法在模拟过程中在节约系统能量方面存在局限性.
研究的目的:
- 为RT-NEO-Ehrenfest动态开发一个改进的TPB方法,以提高系统节能.
- 为了准确地捕捉量子质子动态在nonadiabatic过程中.
- 为了解决以前的TPB方法的节能缺陷.
主要方法:
- 为RT-NEO-Ehrenfest动态提出了一个恒温式TPB方法.
- 动态调整质子动量运算符的尺寸,以保持系统的能量保存.
- 应用了该方法来模拟o-hydroxybenzaldehyde中激发状态的分子内质子转移.
主要成果:
- 恒温式TPB方法显著改善了系统的节能.
- 与最初的TPB方法相比,该方法保持了量子质子动态的准确性.
- 在模型系统 (o-hydroxybenzaldehyde) 中成功应用.
结论:
- 拟议的恒温式TPB方法为模拟RT-NEO-Ehrenfest动态中的量子质子转移提供了更可靠的方法.
- 这一进步导致了对非adiabatic分子过程的更准确,更稳定的模拟.
- 该方法为研究化学反应中的量子效应提供了一个强大的工具.
相关概念视频
The Bohr Model
49.7K
Following the work of Ernest Rutherford and his colleagues in the early twentieth century, the picture of atoms consisting of tiny dense nuclei surrounded by lighter and even tinier electrons continually moving about the nucleus was well established. This picture was called the planetary model since it pictured the atom as a miniature “solar system” with the electrons orbiting the nucleus like planets orbiting the sun. The simplest atom is hydrogen, consisting of a single proton as...
49.7K
The Energies of Atomic Orbitals
23.6K
In an atom, the negatively charged electrons are attracted to the positively charged nucleus. In a multielectron atom, electron-electron repulsions are also observed. The attractive and repulsive forces are dependent on the distance between the particles, as well as the sign and magnitude of the charges on the individual particles. When the charges on the particles are opposite, they attract each other. If both particles have the same charge, they repel each other.
23.6K
Atomic Nuclei: Nuclear Spin State Population Distribution
894
Near absolute zero temperatures, in the presence of a magnetic field, the majority of nuclei prefer the lower energy spin-up state to the higher energy spin-down state. As temperatures increase, the energy from thermal collisions distributes the spins more equally between the two states. The Boltzmann distribution equation gives the ratio of the number of spins predicted in the spin −½ (N−) and spin +½ (N+) states.
894
Atomic Nuclei: Nuclear Relaxation Processes
594
In the absence of an external magnetic field, nuclear spin states are degenerate and randomly oriented. When a magnetic field is applied, the spins begin to precess and orient themselves along (lower energy) or against (higher energy) the direction of the field. At equilibrium, a slight excess population of spins exists in the lower energy state. Because the direction of the magnetic field is fixed as the z-axis, the precessing magnetic moments are randomly oriented around the z-axis.
594
The Quantum-Mechanical Model of an Atom
41.6K
Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of a particle moving in quantized circular orbits, Erwin Schrödinger extended de Broglie’s work by deriving what is now known as the Schrödinger equation. When Schrödinger applied his equation to hydrogen-like atoms, he was able to reproduce Bohr’s expression for the energy and, thus, the Rydberg formula governing...
41.6K
Atomic Nuclei: Nuclear Spin State Overview
819
NMR-active nuclei have energy levels called 'spin states' that are associated with the orientations of their nuclear magnetic moments. In the absence of a magnetic field, the nuclear magnetic moments are randomly oriented, and the spin states are degenerate. When an external magnetic field is applied, the spin states have only 2 + 1 orientations available to them. A proton with = ½ has two available orientations. Similarly, for a quadrupolar nucleus with a nuclear spin value of...
819

